tip

filter header tooltip.

Example

columns: [{
  index: 'age',
  title: 'Age',
  type: 'number',
  filter: {
    header: true,
    tip: [
      'Contains: 30',
      'Less than: <30',
      'More than: >30',
      'Equal: =30',
      'Not Equal: !=30',
      'Composite: <30,>5'
    ].join("")
  }
},{
...

Default

undefined